Earlier quoted context omitted.
Honest question: how? I've never seen anyone who's obese and having a diet that made me go "huh that's odd how can they be obese?" While the inverse occasionally has been true, generally people who I consider in good shape appear to eat less, and less greasy food. So while there might be exceptions it seems to be a damn good rule of thumb to me.
> I've never seen anyone who's obese and having a diet that made me go "huh that's odd how can they be obese?" Your question isn't refuting OPs claim: the people you are observing to be fat are fat because of their carb/sugar intake, not fat. i.e. if you just fed someone large amounts of protein and fat they would be lean; it is the sugar and carbs that make them fat.
A large amount of protein would make them fat - experiments have shown that about 8% of ingested protein gets converted to glucose in the liver:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636610/
The authors calculated that ∼18 g (79%) of the 23 g of ingested protein could be accounted for by deamination; thus those carbon skeletons were available for gluconeogenesis and release of new glucose into the circulation. The remainder, presumably, was used for new protein synthesis.
The total amount of glucose entering the circulation from all sources was calculated to be 50 g over the 8-h period. However, only 4 g (8%) could be attributed to the ingested protein.